World Population Prospects The 2002 Revision

Transcription

1 ESA/P/WP February 2003 ENGLISH ONLY World Population Prospects The 2002 Revision Highlights

2 NOTE The designations employed in this report and the material presented in it do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The term country as used in the text of this report also refers, as appropriate, to territories or areas. The designations more developed, less developed and least developed countries, areas or regions are intended for statistical convenience and do not necessarily express a judgement about the stage reached by a particular country or area in the developing process. ii World Population Prospects: The 2002 Revision

3 PREFACE This report presents the highlights from the results of the 2002 Revision of the official world population estimates and projections prepared by the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. The 2002 Revision is the eighteenth round of global demographic estimates and projections undertaken by the Population Division since The full results of the 2002 Revision will be presented in a series of three volumes currently under preparation. The first volume 1 will provide the comprehensive tables presenting the major demographic indicators for each country for ; the second volume 2 will contain the distributions by age and sex of the population of each country for the period , and the third volume 3 will be devoted to an analysis of the results obtained. Data will also be distributed in digital form. Interested users can purchase a CD- Rom containing the major results of the 2002 Revision. A description of data contained in the CD-Rom and an order form will be posted on the Population Division s web site (see address below). Responsibility for the 2002 Revision rests with the Population Division. Preparation of the 2002 Revision was facilitated by the collaboration of the regional commissions, the specialized agencies and other relevant bodies of the United Nations with the Population Division. In particular, a major source of official national population statistics used in the preparation of these estimates and projections is the United Nations Demographic Yearbook and its accompanying databases, produced and maintained by the United Nations Statistics Division, Department of Economic and Social Affairs. The Population Division is grateful to the Statistics Division for its continuing cooperation. Selected output from the 2002 Revision as well as other population information may be accessed on the world wide web site of the Population Division at For further information about the 2002 Revision, please contact Mr. Joseph Chamie, Director, Population Division, United Nations, New York, NY 10017, USA (fax: ). 1 World Population Prospects: The 2002 Revision, vol. I, Comprehensive Tables (United Nations publication, forthcoming). 2 World Population Prospects: The 2002 Revision, vol. II, Sex and Age Distribution of the World Population (United Nations publication, forthcoming). 3 World Population Prospects: The 2002 Revision, vol. III, Analytical Report (United Nations publication, forthcoming). World Population Prospects: The 2002 Revision iii

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5 EXECUTIVE SUMMARY The 2002 Revision is the eighteenth round of official United Nations population estimates and projections prepared by the Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat. These are used throughout the United Nations system as the basis for activities requiring population information. The 2002 Revision of the official United Nations population estimates and projections breaks new ground in terms of the assumptions made on future human fertility and the impact of the HIV/AIDS epidemic. For the first time, the United Nations Population Division projects that future fertility levels in the majority of developing countries will likely fall below 2.1 children per woman, the level needed to ensure the long-term replacement of the population, at some point in the twenty-first century. By 2050, the medium variant of the 2002 Revision projects that 3 out of every 4 countries in the less developed regions will be experiencing below-replacement fertility. This change in assumptions represents the third and final phase in a process of assessment of future trends in fertility. In 1997 the Population Division convened a meeting of experts to review the guidelines for the projection of fertility in countries with below-replacement fertility. 1 As a result of the deliberations of that meeting the fertility of low-fertility countries was maintained below replacement level during the whole projection period in the 1998 Revision. In 2001, a similar meeting of experts was convened to discuss prospects for countries where fertility had not yet begun to decline or where fertility declines were incipient. 2 Already the 2000 Revision projected that fertility in those countries would decline more slowly than in the 1998 Revision and their pace of fertility decline is not projected to be much faster in the 2002 Revision. Lastly, in 2002 a meeting of experts discussed guidelines on how to project the future fertility of intermediate-fertility countries, that is, those that had already experienced significant fertility decline but had not yet reached levels of fertility below replacement. 3 The projections of fertility in the 2002 Revision reflect the conclusions reached at that meeting. A second important change in the 2002 Revision is that it anticipates a more serious and prolonged impact of the HIV/AIDS epidemic in the most affected countries than previous revisions. The impact of the disease is explicitly modelled for 53 countries, up from the 45 considered in the 2000 Revision. The dynamics of the epidemic are assumed to remain unchanged until Thereafter prevalence levels are assumed to decline in a manner consistent with modifications of behaviour that reduce the rates of recruitment into the high risk group as well as the chances of infection among those engaging in high risk behaviour. The resulting HIV prevalence levels remain relatively high until 2010 and then decline, but are still substantial by mid-century (see annex table 17). As a consequence of these changes, the 2002 Revision projects a lower population in 2050 than the 2000 Revision did: 8.9 billion instead of 9.3 billion according to the medium variant. About half of the 0.4 billion difference in these projected populations results from an increase in the number of projected deaths, the majority stemming from higher projected levels of HIV 1 Below Replacement Fertility, Population Bulletin of the United Nations, Special Issue Nos. 40/41, 1999 (United Nations, 2000). 2 United Nations Workshop on Prospects for Fertility Decline in High Fertility Countries, New York, 9-11 July 2001 (United Nations, ESA/P/WP.167). 3 Completing the Fertility Transition (United Nations, ESA/P/WP.1/Rev.1). World Population Prospects: The 2002 Revision v

6 prevalence. The other half of the difference reflects a reduction in the projected number of births, primarily as a result of lower expected future fertility levels. The results of the 2002 Revision confirm key conclusions from previous revisions and provide new insights into the sensit ivity of population projections to future trends in fertility and mortality. The main findings of the 2002 Revision are summarized below. 1. Despite the lower fertility levels projected and the increased mortality risks to which some populations will be subject, the population of the world is expected to increase by 2.6 billion during the next 47 years, from 6.3 billion today to 8.9 billion in However, the realization of these projections is contingent on ensuring that couples have access to family planning and that efforts to arrest the current spread of the HIV/AIDS epidemic are successful in reducing its growth momentum. The potential for considerable population increase remains high. According to the results of the 2002 Revision, if fertility were to remain constant in all countries at current levels, the total population of the globe could more than double by 2050, reaching 12.8 billion. Even a somewhat slower reduction of fertility than that projected in the medium variant would result in additional billions of people. Thus, if women were to have, on average, about half a child more than according to the medium variant, world population might rise to 10.6 billion in 2050 as projected in the high variant. The low variant, where women have, on average, half a child less than in the medium variant, would result in a 2050 population of 7.4 billion (figure I). 2. World population is currently growing at a rate of 1.2 per cent annually, implying a net addition of 77 million people per year. Six countries account for half of that annual increment: India for 21 per cent; China for 12 per cent; Pakistan for 5 per cent; Bangladesh, Nigeria and the United States of America for 4 per cent each. 3. The increasing diversity of population dynamics among the countries and regions of the world is evident in the results of the 2002 Revision. Whereas today the population of the more developed regions of the world is rising at an annual rate of 0.25 per cent, that of the less developed regions is increasing nearly six times as fast, at 1.46 per cent, and the subset of the 49 least developed countries is experiencing even more rapid population growth (2.4 per cent per year). Such differences, although somewhat dampened, will persist until By that time, the population of the more developed regions will have been declining for 20 years, whereas the population of the less developed regions will still be rising at an annual rate of 0.4 per cent. More importantly, the population of the least developed countries will likely be rising at a robust annual rate of over 1.2 per cent in As a result of these trends, the population of more developed regions, currently at 1.2 billion, is anticipated to change little during the next 50 years. In addition, because fertility levels for most of the developed countries are expected to remain below replacement level during , the populations of 30 developed countries are projected to be smaller by mid-century than today (e.g., 14 per cent smaller in Japan; 22 per cent smaller in Italy, and between 30 and 50 per cent smaller in the cases of Bulgaria, Estonia, Georgia, Latvia, the Russian Federation and Ukraine). vi World Population Prospects: The 2002 Revision

7 Figure I. Estimated and projected population of the world by projection variant, Constant 12 High 10 Medium 8 Low Population (in billions) Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. 5. The population of the less developed regions is projected to rise steadily from 4.9 billion in 2000 to 7.7 billion in 2050 (medium variant). Particularly rapid growth is expected among the least developed countries whose population is projected to rise from 668 million to 1.7 billion despite the fact that their fertility is projected to decline markedly in the future (from 5.1 children per woman today to 2.5 children per woman in ). With sustained annual growth rates higher than 2.5 per cent between 2000 and 2050, the populations of Burkina Faso, Mali, Niger, Somalia, Uganda and Yemen are projected to quadruple, passing from 85 million to 369 million in total. World Population Prospects: The 2002 Revision vii

8 6. Large population increments are expected among the most populous countries even if their fertility levels are projected to be low. Thus, during , eight countries (India, Pakistan, Nigeria, the United States of America, China, Bangladesh, Ethiopia and the Democratic Republic of Congo, in order of population increment) are expected to account for half of the world s projected population increase. 7. The past 50 years witnessed a remarkable reduction of fertility levels in the less developed regions, with total fertility falling from 6 to 3 children per woman. Over the next 50 years, fertility in the less developed regions is expected to reach replacement level in and fall below it thereafter. However, average fertility in the less developed regions as a whole is still expected to be slightly above 2 children per woman in , mainly because of the increasing heterogeneity of population dynamics among developing countries. Thus, the 49 least developed countries are expected to have a total fertility of 2.5 children per woman in , well above replacement level. That is, the 2002 Revision foresees that by mid-century there will still be a significant number of countries where the transition to below-replacement fertility will not be completed. 8. Increasing diversity is also evident with respect to future mortality levels. At the world level, life expectancy at birth is likely to rise from 65 years today to 74 years in But whereas more developed regions, whose life expectancy today is estimated at 76 years, will see it rise to 82 years, that of less developed regions will remain considerably below, reaching 73 years by mid-century (up from 63 years today). In the group of least developed countries, many of which are highly affected by the HIV/AIDS epidemic, life expectancy today is still below 50 years and is not expected to exceed 67 years by So, although the gap in life expectancy between the different groups of countries is expected to narrow, major differences in the probabilities of survival will remain evident by mid-century. 9. The 2002 Revision indicates a worsening of the impact of the HIV/AIDS epidemic in terms of increased morbidity, mortality and population loss. Although the probability of being infected by HIV is assumed to decline significantly in the future (particularly after 2010), the long-term impact of the epidemic remains dire. Over the current decade, the number of excess deaths because of AIDS among the 53 most affected countries is estimated at 46 million and that figure is projected to ascend to 278 million by Despite the devastating impact of the HIV/AIDS epidemic, the populations of the affected countries are generally expected to be larger by mid-century than today, mainly because most of them maintain high to moderate fertility levels. However, for the seven most affected countries in Southern Africa, where current HIV prevalence is above 20 per cent, the population is projected to increase only slightly, from 74 million in 2000 to 78 million in 2050, and outright reductions in population are projected for Botswana, Lesotho, South Africa and Swaziland. 10. The deeper reductions of fertility projected in the 2002 Revision result in a faster ageing of the population of developing countries than in previous revisions. Globally, the number of older persons (60 years or over) will nearly triple, increasing from 606 million in 2000 to nearly 1.9 billion by Whereas 6 of every 10 of those older persons live today in less developed regions, by 2050, 8 of every 10 will do so. An even more marked increase is expected in the number of the oldest-old (80 years or over) at the global level: viii World Population Prospects: The 2002 Revision

9 from 69 million in 2000 to 377 million in In less developed regions, the rise will be from 32 million to 265 million, again implying that most oldest old will live in less developed countries by In more developed regions, the population aged 60 or over currently constitutes 19 per cent of the population; by 2050 it will account for 32 per cent of the population. The elderly population in more developed regions has already surpassed the child population (persons aged 0-14) and by 2050 there will be 2 elderly persons for every child. In the less developed regions, the proportion of the population aged 60 or over will rise from 8 per cent in 2000 to close to 20 per cent in Increases in the median age, the age at which 50 per cent of the population is older and 50 per cent is younger than that age, reflect the ageing of the population. At the world level, the median age rose by scarcely three years between 1950 and 2000, from 23.6 years to 26.4 years, largely because most populations in less developed countries remained young. Over the next 50 years, however, the world s median age will rise by nearly 10 years, to reach 37 years in Among developed countries, 13 are expected to have a median age of 50 years or more, with Japan, Latvia and Slovenia (each with a median age of about 53 years), and the Czech Republic, Estonia, Italy and Spain (each with a median age of about 52 years) leading the list. In addition, three developing countries (Armenia, the Republic of Korea and Singapore) will also be in that group. At the other end of the spectrum, Angola, Burkina Faso, Mali, Niger, Somalia, Uganda and Yemen expect to have still young populations, with median ages lower than 23 years in International migration is projected to remain high during the first half of the century. The more developed regions are expected to remain net receivers of international migrants, with an average gain of about 2 million migrants per year over the next 50 years. Averaged over the period, the main net gainers of international migrants are projected to be the United States (1.1 million annual net migrants), Germany (211 thousand), Canada (173 thousand), the United Kingdom (136 thousand) and Australia (83 thousand), whereas the major net senders are projected to be China (-303 thousand annual net number of migrants), Mexico, (-267 thousand), India (-222 thousand), the Philippines (-184 thousand) and Indonesia (-180 thousand). World Population Prospects: The 2002 Revision ix

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11 CONTENTS Preface... Explanatory notes... Executive Summary... Page iii xiv v I. WORLD POPULATION TRENDS... 1 II. FERTILITY... 7 III. THE DEMOGRAPHIC IMPACT OF HIV/AIDS IV. POPULATION AGEING V. ASSUMPTIONS UNDERLYING THE 2002 REVISION VI. OBTAINING DATA FROM WORLD POPULATION PROSPECTS: THE 2002 REVISION No. TABLES 1. Estimated and projected population of the world, major development groups and major areas, 1950, 2000, 2003 and 2050 according to fertility variant Estimated and projected total fertility for the world, major development groups and major areas, and according to fertility variant Expectation of life at birth for the world, major development groups and major areas, and Distribution of countries and areas and of the world population according to the level of total fertility in , and Distribution of countries and areas and of the world population according to the level of total fertility in , low, medium and high variants Difference in projected population with and without AIDS and percentage difference for groups of affected countries in major areas, 2000, 2015 and Excess deaths in a projection with AIDS in relation to a projection assuming no AIDS for groups of affected countries in major areas, , and Expectation of life at birth with and without AIDS for selected affected countries, , and Median age by major area, 1950, 2000 and 2050 (medium variant) Average annual growth rates of the total population and the population in broad age groups, by major area, (medium variant) Projection variants in terms of assumptions for fertility, mortality and international migration FIGURES 1. Annual growth rate for the world and major development groups, World Population Prospects: The 2002 Revision xi

12 No. Page 2. Total fertility trajectories in the medium variant for the world and major development groups, Expectation of life at birth for the world and major development groups, Annual population growth rate projected with and without AIDS, Botswana, to Life expectancy at birth in Zimbabwe with and without AIDS, Population with and without AIDS, South Africa, ANNEX TABLES 1. Total population by sex and sex ratio, by country, 2003 (medium variant) Total population by country, 1950, 2000, 2015, 2025 and 2050 (medium variant) Total fertility, by country, for selected periods (medium variant) Life expectancy at birth (both sexes combined), by country, for selected periods Infant mortality rate, by country, for selected periods Annual population growth rate, by country, for selected periods (medium variant) Percentage distribution of the population in selected age groups, by country, 2000 and 2050 (medium variant) Median age of the population, by country, 1950, 2000 and 2050 (medium variant) Countries with a population of 50 million or more, 1950, 2000 and 2050 (medium variant) Countries accounting for 75 per cent of population growth in the world in , and (medium variant) Ten countries or areas with the highest and ten countries or areas with the lowest total fertility, and (medium variant) Ten countries or areas with the highest and ten countries or areas with the lowest life expectancy at birth, and Ten countries or areas with the highest and ten countries or areas with the lowest rates of population growth, and (medium variant) Ten countries or areas with the highest and ten countries or areas with the lowest rates of natural increase, and (medium variant) Ten countries or areas with the oldest and ten countries or areas with the youngest populations, 2000 and 2050 (medium variant) Countries or areas whose population is projected to decrease between 2000 and 2050 (medium variant) HIV prevalence in countries most affected by the HIV/AIDS epidemic for year of peak prevalence, 2001 and Life expectancy at birth in the countries most affected by the HIV/AIDS epidemic, projected with AIDS and without AIDS, , and Difference in life expectancy at birth without and with AIDS in the countries most affected by the HIV/AIDS epidemic, , and Number of deaths in the countries most affected by the HIV/AIDS epidemic, estimated and projected with AIDS and without AIDS, , and xii World Population Prospects: The 2002 Revision

13 No. Page 21. Excess number of deaths estimated and projected with AIDS versus without AIDS in the countries most affected by the HIV/AIDS epidemic, , and Population in the countries most affected by the HIV/AIDS epidemic, estimated and projected with AIDS and without AIDS, 2000, 2015 and Difference in estimated and projected population without and with AIDS in the countries most affected by the HIV/AIDS epidemic, 2000, 2015 and World Population Prospects: The 2002 Revision xiii

14 Explanatory notes Tables presented in this report make use of the following symbols: Two dots (..) indicate that data are not available or are not separately reported. An em dash ( ) indicates that the amount is nil or negligible. A hyphen (-) indicates that the item is not applicable. A minus sign (-) before a figure indicates a decrease. A full stop (.) is used to indicate decimals. Years given start on 1 July. Use of a hyphen (-) between years, for example, , signifies the full period involved, from 1 July of the first year to 1 July of the second year. Numbers and percentages in tables do not necessarily add to totals because of rounding. Countries and areas are grouped geographically into six major areas: Africa; Asia; Europe; Latin America and the Caribbean; Northern America; and Oceania. These major areas are further divided into 21 geographical regions. In addition, for statistical convenience, the regions are classified as belonging to either of two categories: more developed or less developed. The less developed regions include all the regions of Africa, Asia (excluding Japan), and Latin America and the Caribbean, as well as Melanesia, Micronesia and Polynesia. The more developed regions comprise Australia/New Zealand, Europe, Northern America and Japan. The group of least developed countries currently comprises 49 countries: Afghanistan, Angola, Bangladesh, Benin, Bhutan, Burkina Faso, Burundi, Cambodia, Cape Verde, Central African Republic, Chad, Comoros, Democratic Republic of the Congo, Djibouti, Equatorial Guinea, Eritrea, Ethiopia, Gambia, Guinea, Guinea-Bissau, Haiti, Kiribati, Lao People s Democratic Republic, Lesotho, Liberia, Madagascar, Malawi, Maldives, Mali, Mauritania, Mozambique, Myanmar, Nepal, Niger, Rwanda, Samoa, Sao Tome and Principe, Senegal, Sierra Leone, Solomon Islands, Somalia, Sudan, Togo, Tuvalu, Uganda, United Republic of Tanzania, Vanuatu, Yemen and Zambia. The following abbreviations have been used: AIDS HIV UNAIDS Acquired immunodeficiency syndrome Human immunodeficiency virus Joint United Nations Programme on HIV/AIDS xiv World Population Prospects: The 2002 Revision

15 I. WORLD POPULATION TRENDS The world population reached 6.3 billion at the beginning of 2003 and is projected to grow to 8.9 billion by 2050, according to the medium variant (table 1). In that variant, total fertility at the world level is expected to decline from 2.83 children per woman in to 2.02 children per woman in , and the expectation of life at birth is expected to increase from 65 years to 74 years. As a consequence of the expected reduction of fertility, the population growth rate is projected to drop from 1.35 per cent per year in to 0.33 per cent per year in TABLE 1. ESTIMATED AND PROJECTED POPULATION OF THE WORLD, MAJOR DEVELOPMENT GROUPS AND MAJOR AREAS, 1950, 2000, 2003 AND 2050 ACCORDING TO FERTILITY VARIANT Estimated population (millions) Population in 2050 (millions) Major area Low Medium High Constant World More developed regions Less developed regions Least developed countries Other less developed countries Africa Asia Latin America and the Caribbean Europe Northern America Oceania Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. Population growth is projected to slow down in both the more developed and the less developed regions. However, whereas the growth rate remains positive for the less developed regions until 2050, it turns negative after 2030 for the more developed regions. By , the population in the more developed regions is projected to be declining at a rate of per cent per year, whereas the population of the less developed regions will be growing at a robust rate of 0.40 per cent per year (figure 1). The difference in growth trajectories between the more developed and the less developed regions is mainly the product of their current levels of fertility and the path fertility is expected to follow in the future. Although considerable differences in fertility exist among the countries of the more developed regions, in virtually all of them fertility is currently below replacement level (i.e. below 2.1 children per woman) and, although it is projected to rise somewhat in the future, it will remain below replacement level until Thus, for the more developed regions as a whole, total fertility is expected to decline from 1.58 children per woman in to 1.56 children per woman in and then to rise slowly to 1.85 children per woman in (figure 2). World Population Prospects: The 2002 Revision 1

16 Figure 1. Annual growth rate for the world and major development groups, Annual growth rate (percentage) Period World More developed regions Less developed regions Least developed countries Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. In contrast, in the less developed regions as a whole, fertility is still above replacement level (at 3.11 children per woman in and 2.92 in ) and is expected to remain above replacement level until , when it reaches 2.22 children per woman. At that time, the net reproduction rate is expected to be 1 daughter per woman for the first time, implying that true replacement level is reached, given the expected mortality level for the period. After 2035, the net reproduction rate in the less developed regions drops below 1 as total fertility continues to decline, reaching 2.04 children per woman in However, these averages mask the considerable heterogeneity that characterizes fertility levels in developing countries. Indeed, the less developed regions include both low-fertility countries such as China, where fertility is already below replacement level, and a number of high-fertility countries, such as Afghanistan, Angola, Burkina Faso, Burundi, Guinea-Bissau, the Democratic Republic of the Congo, Mali, Niger, Somalia, Uganda or Yemen, where fertility is high and has either shown no signs of declining yet or is only beginning to decline. For the latter group, fertility levels over the decade are expected to remain high and although important reductions of fertility are projected to occur by 2050, their total fertility by is expected be in the range of 2.5 to 3.9 children per woman, still moderately high. 2 World Population Prospects: The 2002 Revision

17 Figure 2. Total fertility trajectories in the medium variant for the world and major development groups, Total fertility (children per woman) Period World More developed regions Less developed regions Least developed countries Source: Population Division of the Department of Economic and Social Affairs of the United Nat ions Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. Most high-fertility countries, including those that have not yet experienced a decline of fertility or where the decline is incipient, belong to the group of least developed countries. Relatively high fertility is expected to characterize that group of countries in the future (table 2). In , the 49 least developed countries had a total fertility of 5.46 children per woman, which is projected to decline to 2.47 children per woman in , a level consistent with a net reproduction rate of 1.1 daughters per woman and that is, therefore, above replacement level. In contrast, the rest of the countries in the less developed regions exhibit as a group a total fertility of 2.79 children per woman in and are projected to have 1.90 children per woman in , a level consistent with a net reproduction rate of 0.89 daughters per woman and clearly below replacement level. In fact, the net reproduction rate of the less developed countries that do not belong to the group of the least developed is projected to reach a net reproduction rate of 1 daughter per woman in and to have, therefore, a fertility under replacement level thereafter. World Population Prospects: The 2002 Revision 3

18 TABLE 2. ESTIMATED AND PROJECTED TOTAL FERTILITY FOR THE WORLD, MAJOR DEVELOPMENT GROUPS AND MAJOR AREAS, AND ACCORDING TO FERTILITY VARIANT Total fertility (average number of children per woman) Major area Low Medium High Constant World More developed regions Less developed regions Least developed countries Other less developed countries Africa Asia Latin America and the Caribbean Europe Northern America Oceania Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. TABLE 3. EXPECTATION OF LIFE AT BIRTH FOR THE WORLD, MAJOR DEVELOPMENT GROUPS AND MAJOR AREAS, AND Major area World More developed regions Less developed regions Least developed countries Other less developed countries Africa Asia Latin America and the Caribbean Europe Northern America Oceania Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. 4 World Population Prospects: The 2002 Revision

19 Equally striking are the differences in expectation of life at birth (table 3 and figure 3). The more developed regions experience the lowest mortality and have, therefore, higher levels of life expectancy at birth than the less developed regions as a whole (75 years versus 63 years in ). Although the gap between the two groups of countries is expected to narrow over the next 50 years, by the more developed regions are still expected to have considerably higher life expectancy at birth than the less developed regions (82 years versus 73 years). Within both the more developed and the less developed regions, certain groups of countries have higher mortality than the rest. For example, in the more developed regions, Eastern Europe has experienced increased mortality over the past decade and exhibits relatively low levels of life expectancy at birth (68 years in ). By , Eastern Europe s projected life expectancy, at 77 years, is the lowest among those of the more developed regions. Figure 3. Expectation of life at birth for the world and major development groups, Expectation of life at birth (years) Period World More developed regions Less developed regions Least developed countries Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. World Population Prospects: The 2002 Revision 5

20 Among the less developed regions, those that are highly affected by the HIV/AIDS epidemic have some of the lowest life expectancies recorded in recent times and are projected to experience continued high mortality over the next 50 years. Sub-Saharan Africa, in particular, with 37 highly affected countries in 2001, had an estimated life expectancy of 47 years in , two years lower than it was 10 years earlier (49 years). Furthermore, life expectancy is expected to keep on declining over the next decade, to 46 years on average. Although the incidence of HIV infection is projected to decline, particularly after 2010, by life expectancy in sub-saharan Africa is still expected to be the lowest among the world s major areas (63 years). The 49 least developed countries, which include 28 of the countries that are highly affected by HIV/AIDS, already experience fairly high mortality levels. Their life expectancy at birth was 49 years in and is expected to remain relatively low during the next 50 years, reaching 66 years in Despite being subject to high mortality, the population of the least developed countries is expected to more than double between 2000 and 2050, rising from 668 million to 1.68 billion. The high fertility levels prevailing there are largely responsible for the increase. Growth will also be substantial in the rest of the developing countries, whose population is projected to increase from 4.2 billion to 6 billion between 2000 and Consequently, the population of the less developed regions as a whole is projected to increase from 4.9 billion in 2000 to 7.7 billion in Such an increase in size is moderate if one considers that, were fertility to remain constant at current levels in the less developed countries, their total population would rise to 11.6 billion in 2050, 3.9 billion more than projected under the medium variant. In the more developed regions, the population is projected to grow slightly between 2000 and 2030, rising from 1.19 billion to 1.24 billion, only to decline thereafter to reach 1.22 billion by If fertility were to remain constant at the levels reached in , the total population in 2050 would not be very different (1.18 billion), partly because a considerable part of the population growth in the more developed regions is associated with the projected net inflow of international migrants. The difference between the projected population in 2050 according to the 2002 Revision (8.9 billion) and that projected in the 2000 Revision 4 (9.3 billion) is a deficit in the 2002 Revision of 403 million people. The higher mortality levels projected for the countries affected by the HIV/AIDS epidemic in the 2002 Revision are responsible for about half that deficit or 193 million additional deaths. The rest of the difference is attributable to less births projected in the 2002 Revision than in the 2000 Revision, most of which are the result of the lower levels of fertility projected in the former. The HIV/AIDS epidemic also contributes to reduce the number of projected births by reducing the population of women in the reproductive ages, but this effect is smaller than that associated with the reduction of fertility. 4 World Population Prospects: The 2000 Revision, vol. I, Comprehensive Tables (United Nations publication, Sales no. E.01.XIII.8); vol. II, Sex and Age (Sales no. E.01.XIII.9); and vol. III, Analytical Report (Sales no. E.01.XIII.20). 6 World Population Prospects: The 2002 Revision

21 II. FERTILITY According to the 2002 Revision, total fertility that is, the average number of children a woman would bear if fertility rates remained unchanged during her lifetime was 2.83 children per woman in at the world level. This average results from very varied experiences at the country level. In , 59 countries or areas (44 of them located in the more developed regions) experienced fertility levels below 2.1 children per woman or replacement level 5, whereas 133 countries or areas (132 of which are located in the less developed regions) experienced total fertility levels at or above 2.1 children per woman. Among the latter, 47 had total fertility levels at or above 5 children per woman, and the majority of them are among the countries classified as least developed (table 4). TABLE 4. DISTRIBUTION OF COUNTRIES AND AREAS AND OF THE WORLD POPULATION ACCORDING TO THE LEVEL OF TOTAL FERTILITY IN , AND Population (millions) Number of countries Range of total fertility Greater than Between 6 and Between 5 and Between 4 and Between 3 and Between 2.1 and Less than TOTAL Percentage Greater than Between 6 and Between 5 and Between 4 and Between 3 and Between 2.1 and Less than Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. In 2000, the 59 countries where total fertility was below repla cement level accounted for 44 per cent of the world s population, or 2.6 billion people, whereas the countries with fertility at or above-replacement level had 3.3 billion persons in 2000, or 56 per cent of the total. Because of their low fertility and the expectation that it will not rise markedly in the future, the countries with below-replacement fertility are projected to have only a slightly larger population in 2050 than 5 Replacement-level fertility is the level that needs to be sustained over the long run to ensure that a population replaces itself. For most countries, replacement level is close to 2.1 children per woman. World Population Prospects: The 2002 Revision 7

22 today (2.8 billion people). In contrast, the countries whose fertility is currently above replacement level are expected to experience a marked population increase, reaching 6 billion by 2050 and accounting then for 68 per cent of the global population. The pace of fertility decline during has varied significantly among developing countries. Although most countries in the less developed regions are already far advanced in the transition from high to low fertility, there are 24 countries that still had total fertility levels of 6 children or higher in and 15 among them have yet to exhibit significant fertility reductions. Although the fertility of those 24 countries is projected to decline markedly during , none is expected to reach 2.1 children per woman by 2050 in the medium variant. As a result of those trends, their population is expected to rise from 301 million in mid-1997 to a billion in The 24 countries involved Afghanistan, Angola, Benin, Burkina Faso, Burundi, Chad, Congo, Democratic Republic of the Congo, Djibouti, Ethiopia, Guinea, Guinea-Bissau, Liberia, Madagascar, Malawi, Mali, Mauritania, Niger, Rwanda, Sierra Leone, Somalia, Uganda, Yemen and Zambia with the sole exception of Congo, all belong to the group of least developed countries, and several are already highly affected by the HIV/AIDS epidemic. Moreover, a number of them have been experiencing civil strife and political instability in recent years, factors that militate against the provision of basic services for the population. Clearly, the continuation of rapid population growth poses serious challenges to their future development. Despite the importance high-fertility countries have for the future of world population, in they accounted for a low 5.2 per cent of the world population. Also small was the share of countries with total fertility levels ranging from 5 to 6 children per woman, which amounted to 7 per cent of the world population. In , the bulk of the population of the developing world lived in countries where total fertility levels ranged from 2.1 to 5 children per woman, countries that accounted for 44 per cent of the world population. In the 2002 Revision, the total fertility of those countries is projected to decline below 2.1 children per woman by 2050, that is, their future fertility is no longer constrained to remain at replacement level (2.1 children per woman) once that level is reached. Although not all the countries with a total fertility in the range of 2.1 to 5 children per woman reach the floor level of 1.85 children per woman (see assumptions in chapter V), the majority does. Consequently, by , the medium variant projects that 84 per cent of the world s population will live in countries or areas with a total fertility below 2.1 children per woman. A total of 154 countries or areas will be in that group, among which 123 are projected to have a total fertility of 1.85 children per woman in (table 5). The remaining 38 countries or areas are projected to have total fertility levels at or above 2.1 children per woman in By that time, they will account for 16 per cent of the world s population, nearly double the share they had in 2000 when those 38 countries accounted for about 8 per cent of the world population. At the world level, the effect of projecting that the majority of developing countries will reach total fertility levels below 2.1 children per woman in the medium variant before 2050 leads to a total fertility of 2.02 children per woman in In more developed regions, total fertility in the medium variant is projected to be 1.85 children per woman by then, whereas in the less developed regions total fertility remains above 2 children per woman until 2050 (2.04 children per woman in ). That is, although the difference in total fertility between the more and the less developed regions narrows considerably, by mid-century the less developed 8 World Population Prospects: The 2002 Revision

23 regions as a whole are still expected to have a higher total fertility than the more developed regions. That difference is maintained in all projection variants. Total fertility in the low variant is expected to be 1.35 children per woman in more developed regions and 1.56 children per woman in the less developed regions. In the high variant, total fertility is projected to be 2.35 in the more developed regions and 2.52 in the less developed regions. TABLE 5. DISTRIBUTION OF COUNTRIES AND AREAS AND OF THE WORLD POPULATION ACCORDING TO THE LEVEL OF TOTAL FERTILITY IN , LOW, MEDIUM AND HIGH VARIANTS Range of total fertility Population in 2048 (millions) Number of countries in Percentage of population Percentage of countries Low variant Between 3 and Between 2.1 and Less than Equal to TOTAL Medium variant Between 3 and Between 2.1 and Less than Equal to TOTAL High variant Between 4 and Between 3 and Between 2.35 and Equal to TOTAL Source: Population Division of the Department of Economic and Social Affairs of the United Nations Secretariat (2003). World Population Prospects: The 2002 Revision. Highlights. New York: United Nations. World Population Prospects: The 2002 Revision 9

24 III. THE DEMOGRAPHIC IMPACT OF HIV/AIDS Compared to previous revisions, the 2002 Revisio n anticipates a more serious and prolonged impact of the HIV/AIDS epidemic in the most affected countries. The impact of HIV/AIDS is explicitly modelled for 53 countries, up from 45 in the 2000 Revision. In most of these countries, HIV prevalence in 2001 was estimated to be 2 per cent or more among the population aged (see annex table 17). In addition, a few populous countries with lower prevalence levels were included because they had a large number of persons living with HIV (more than one million persons). Of the 53 countries, 38 are in Saharan Africa (Angola, Benin, Botswana, Burundi, Burkina Faso, Cameroon, Central African Republic, Chad, Congo, Côte d'ivoire, Democratic Republic of the Congo, Djibouti, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Malawi, Mali, Mozambique, Namibia, Nigeria, Rwanda, Sierra Leone, South Africa, Sudan, Swaziland, Togo, Uganda, United Republic of Tanzania, Zambia, Zimbabwe), five in Asia (Cambodia, China, India, Myanmar and Thailand), eight in Latin America and the Caribbean (Bahamas, Belize, Brazil, Dominican Republic, Guyana, Haiti, Honduras, Trinidad and Tobago), and one each in Europe (Russian Federation) and Northern America (United States of America). Of the 37.1 million adults in the world infected by HIV by 2001, 34.6 million or 93 per cent resided in these 53 countries 6. The dynamics of the HIV/AIDS epidemic, as estimated by UNAIDS, are assumed to remain unchanged until Thereafter prevale nce levels are assumed to decline in a manner consistent with modifications of behaviour that reduce the rates of recruitment into high risk groups as well as the chances of infection among those engaging in high risk behaviour. In many countries, the estimated peak prevalence has already passed (annex table 17), but prevalence levels are assumed to remain relatively high until 2010 when more rapid decline will begin. By 2050, prevalence levels are lower but still substantial in the most highly affected countries. The 2002 Revision confirms yet again the devastating toll AIDS has in terms of increased morbidity, mortality and population loss. The population of the 53 affected countries in 2050 is projected to be 479 million lower than it would have been in the absence of AIDS. Between 2000 and 2050, 278 million excess deaths persons who are projected to die earlier than they would have in the absence of AIDS will occur. Over the same period, there will be a deficit of 178 million births due to the early deaths of women of childbearing age and the effect of HIV on the fertility of women living with the disease. In the 38 highly affected countries of Africa, the population by 2015 is projected to be 91 million less, or 10 per cent lower, than it would have been without AIDS (table 6). The number of excess deaths in these countries will be nearly 15 million during (table 7), representing an increase of 36 per cent over the number of deaths projected in the absence of AIDS. The demographic impact of AIDS is even more dramatic in the seven countries of Africa with the highest HIV prevalence levels (at or above 20 per cent), namely, Botswana, Lesotho, Namibia, South Africa, Swaziland, Zambia and Zimbabwe. In these countries, the population in 6 Report on the Global HIV/AIDS Epidemic 2002 (Geneva, UNAIDS 2002). 10 World Population Prospects: The 2002 Revision